JP2020529386A - Manufacturing method of electrodes for all-solid-state batteries - Google Patents

Abstract

The method (100) for producing a sintered member which is an electrode containing titanium and sulfur for an all-solid-state battery includes a step (102) of mixing powders and a powder in order to obtain a powder mixture containing titanium and sulfur. A step of pressing a member containing a mixture (106), a step of sintering a member under a partial pressure of 200 Pa to 0.2 MPa in order to obtain an intermediate sintered member containing titanium and sulfur (108), and titanium. In order to obtain a sintered member containing sulfur and sulfur, a step (114) of sintering the intermediate sintered member at a partial pressure of sulfur of 150 Pa or less and a steady temperature of 200 ° C. to 400 ° C. is included, and the solid electrolyte is CuKα. 2θ = 15.08 ° (± 0.50 °), 15.28 ° (± 0.50 °), 15.92 ° (± 0.50 °), 17.5 in X-ray diffraction measurement using a line. ° (± 0.50 °), 18.24 ° (± 0.50 °), 20.30 ° (± 0.50 °), 23.44 ° (± 0.50 °), 24.48 ° (± 0.50 °) Peaks are shown at ± 0.50 °) and 26.66 ° (± 0.50 °) positions.

Description

Fields of Disclosure The present disclosure relates to all-solid-state batteries, and more specifically to solid-state batteries with sulfur-containing solid electrolytes and / or electrodes.

Background of Disclosure All-solid-state batteries enable the provision of battery packs with high energy densities.

Different materials are being studied for solid electrolytes and / or electrodes for all-solid-state batteries. Of particular interest are titanium and sulfur, 2θ = 15.08 ° (± 0.50 °), 15.28 ° (± 0.50 °), 15. In X-ray diffraction measurements using CuKα rays. 92 ° (± 0.50 °), 17.5 ° (± 0.50 °), 18.24 ° (± 0.50 °), 20.30 ° (± 0.50 °), 23.44 ° It is a material that shows peaks at positions (± 0.50 °), 24.48 ° (± 0.50 °), and 26.66 ° (± 0.50 °). These materials generally have good lithium ion conductivity but low electron conductivity.

Therefore, in order to use these materials as solid electrolytes and / or electrodes, it is necessary to increase their electronic conductivity.

Summary of Disclosure Therefore, according to the embodiments of the present disclosure, there is provided a method for producing a sintered member which is a solid electrolyte and / or an electrode containing titanium and sulfur for an all-solid-state battery. This method involves mixing the powder to obtain a powder mixture containing titanium and sulfur, pressing the member containing the powder mixture, and obtaining an intermediate sintered member containing titanium and sulfur. In order to obtain a step of sintering a member under a sulfur partial pressure of 200 Pa to 0.2 MPa and a sintered member containing titanium and sulfur, intermediate firing is performed at a sulfur partial pressure of 150 Pa or less and a steady temperature of 200 ° C. to 400 ° C. Including the step of sintering the connecting member, the sintered member is 2θ = 15.08 ° (± 0.50 °) and 15.28 ° (± 0.50 °) in the X-ray diffraction measurement using CuKα ray. ), 15.92 ° (± 0.50 °), 17.5 ° (± 0.50 °), 18.24 ° (± 0.50 °), 20.30 ° (± 0.50 °), Peaks are shown at 23.44 ° (± 0.50 °), 24.48 ° (± 0.50 °), and 26.66 ° (± 0.50 °).

According to the embodiments of the present disclosure, there is provided a method for producing a sintered member which is a solid electrolyte and / or an electrode containing titanium and sulfur for an all-solid-state battery. This method involves mixing the powder to obtain a powder mixture containing titanium and sulfur, pressing the member containing the powder mixture, and obtaining an intermediate sintered member containing titanium and sulfur. The step of sintering a member under a sulfur partial pressure of 200 Pa to 0.2 MPa, and in order to obtain a sintered member containing titanium and sulfur, in order to obtain a sintered member, the intermediate sintered member is sintered at a gradient temperature. The maximum temperature of the intermediate sintered member is between 200 ° C. and 400 ° C., and the sintered member is 2θ = 15.08 ° (± 0.) in the X-ray diffraction measurement using CuKα ray. 50 °), 15.28 ° (± 0.50 °), 15.92 ° (± 0.50 °), 17.5 ° (± 0.50 °), 18.24 ° (± 0.50 °) ), 20.30 ° (± 0.50 °), 23.44 ° (± 0.50 °), 24.48 ° (± 0.50 °), and 26.66 ° (± 0.50 °) A peak is shown at the position of.

In X-ray diffraction measurement using a sintered member, that is, CuKα ray, 2θ = 15.08 ° (± 0.50 °), 15.28 ° (± 0.50 °), 15.92 ° (± 0. 50 °), 17.5 ° (± 0.50 °), 18.24 ° (± 0.50 °), 20.30 ° (± 0.50 °), 23.44 ° (± 0.50 °) ), 24.48 ° (± 0.50 °), and 26.66 ° (± 0.50 °) positions, solid electrolytes and / or electrodes generally have good lithium ion conductivity. However, the electron conductivity is low.

By providing these methods, since the member is sintered under a sulfur partial pressure of 200 Pa (Pascal) to 0.2 MPa, the evaporation of sulfur is restricted during sintering, and the intermediate sintered member increases the volume density. Can be obtained. In practice, the evaporation of sulfur is restricted during sintering, increasing the bulk density of the intermediate sintered member. This reduces the porosity of the intermediate sintered member.

The increase in electron conductivity of the solid electrolyte and / or the entire electrode can be achieved by sintering the intermediate sintered member at a sulfur partial pressure of 150 Pa or less and a steady temperature of 200 ° C. to 400 ° C. It is obtained by sintering the intermediate sintered member at a gradient temperature between 200 ° C and 400 ° C.

Intermediate sintering by sintering the intermediate sintered member at a sulfur partial pressure of 150 Pa or less and a steady temperature of 200 ° C to 400 ° C, or at a gradient temperature where the maximum temperature of the intermediate sintered member is between 200 ° C and 400 ° C. By sintering the member, some of the sulfur present in the intermediate sintered member is evaporated and some of the titanium is reduced from Ti ⁴⁺ to Ti ³⁺ or less, i.e. Ti ²⁺ or Ti ⁺ . Will be done. By reducing titanium, the electron conductivity of the sintered member is increased.

In some embodiments, a sulfur partial pressure of 150 Pa or less is obtained by flowing a rare gas or nitrogen through the intermediate sintered member.

In some embodiments, the sulfur partial pressure of 150 Pa or less is obtained by continuously discharging the gas present in the closed vessel containing the intermediate sintered member.

In some embodiments, the intermediate sintered member is sealed in a closed container during sintering at a gradient temperature.

In some embodiments, the sintered member comprises XTi ₂ (PS ₄ ) ₃ , where X is lithium (Li), sodium (Na) or silver (Ag).

In some embodiments, the method comprises the step of amorphizing the powder mixture in order to obtain an amorphized powder mixture.

In some embodiments, sintering under a sulfur partial pressure of 200 Pa to 0.2 MPa comprises a steady sintering temperature of 500 ° C. or lower, preferably 400 ° C. or lower.

Amorphizing the powder mixture makes the powder mixture more reactive. Therefore, the powder mixture can be sintered at a temperature of 500 ° C. or lower.

In some embodiments, sintering under a sulfur partial pressure of 200 Pa to 0.2 MPa comprises a steady sintering time of 20 hours or less, preferably 10 hours or less.

Amorphizing the powder mixture makes the powder mixture more reactive. Therefore, the powder mixture can be sintered in a steady sintering time of 20 hours or less, preferably 10 hours or less.

In some embodiments, a sulfur partial pressure of 200 Pa-0.2 MPa is obtained by evaporating solid sulfur.

In some embodiments, the members are placed in a container and sealed under argon at a pressure of 100 Pa or less, preferably 50 Pa or less.

In some embodiments, the sulfur partial pressure of 200 Pa-0.2 MPa is obtained from the sulfur-containing gas.

The sulfur-containing gas may be a gas such as hydrogen sulfide, carbon sulfide or phosphorus sulfide.
In some embodiments, the member is pressed at a pressure of 25 MPa or higher, preferably 50 MPa or higher, more preferably 75 MPa or higher, 500 MPa or lower, preferably 400 MPa or lower, more preferably 300 MPa or lower.

In some embodiments, the intermediate sintered member is polished and pressed during the two sintering steps.

In some embodiments, the polished and pressed intermediate sintered member is pressed at a pressure of 25 MPa or higher, preferably 50 MPa or higher, more preferably 75 MPa or higher, 500 MPa or lower, preferably 400 MPa or lower, more preferably 300 MPa or lower. To.

It is intended to combine the elements described above with the elements described herein, as long as they are not inconsistent with each other.

It should be understood that both the general description above and the detailed description below are illustration and description only and do not limit the present disclosure as described in the claims.

The accompanying drawings, incorporated herein by reference and in part thereof, illustrate embodiments of the present disclosure and illustrate the principles of the present disclosure with the following description.

It is a flowchart which shows the method which concerns on embodiment of this disclosure. It is a figure which shows the X-ray diffraction spectrum of the sample of this disclosure. It is a figure which shows the X-ray diffraction spectrum of the sample of a comparative example. It is a figure which shows the real part of the electric conductivity which changes according to a frequency. It is a figure which shows the real part of the electric conductivity which changes according to a frequency.

Description of Embodiments Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the examples shown in the accompanying drawings. Where possible, all drawings use the same reference number to refer to the same or similar parts.

FIG. 1 shows a flowchart of the method according to the embodiment of the present disclosure.
Sample 1 is a sample of the present disclosure, and Sample 2 is a sample of a comparative example.

Sample 1 and Sample 2 are both LiTi ₂ (PS ₄ ) ₃ solid electrolytes or electrodes.

All experiments are performed in an argon or vacuum or sulfur atmosphere to avoid contact with air.

With reference to FIG. 1, a method 100 for producing a solid electrolyte and / or an electrode containing titanium and sulfur for an all-solid-state battery will be described using Sample 1.

In step 102, 0.0396 g (grams) of Li ₂ S, 0.5745 g of P ₂ S ₅ and 0.3859 g of Ti S ₂ are mixed to obtain a powder mixture. Li ₂ S (99%, lithium sulfide, Sigma-Aldrich®), P ₂ S ₅ (98%, phosphorus pentasulfide, Sigma-Aldrich®) and TiS ₂ (99.9%, Titanium disulfide, Sigma-Aldrich (registered trademark), is a powder having a purity of 99% by mass or more.

In step 104, which is not an essential step, the powder mixture is amorphized in a planetary grinder (Fritsch, P7). The powder mixture was placed in a zirconium pot under argon. This zirconium pot has a volume of 45 mL (millimeters) and contains 18 zirconium balls with a diameter of 10 mm (millimeters). The amorphized powder mixture was obtained by amorphizing the powder mixture at 370 rpm (rotational speed per minute) for 40 hours.

In step 106, the amorphized powder mixture is pressed at a pressure of 25 MPa or more, preferably 50 MPa or more, more preferably 75 MPa or more, 500 MPa or less, preferably 400 MPa or less, more preferably 300 MPa or less.

For example, a member is formed by pressing 100 mg of an amorphized powder mixture at 200 MPa.

In step 108, an intermediate sintered member containing titanium and sulfur is formed by sintering the member under a sulfur partial pressure of 150 Pa to 0.2 MPa.

For example, 100 mg of material is charged into a glass tube with 5 mg of sulfur flakes (99.99%) from Sigma-Aldrich® and the glass tube is sealed under very low pressure, eg 30 Pa of argon. .. An intermediate sintered member containing titanium and sulfur is formed by sintering the member at a steady temperature of 400 ° C. (Celsius) and a steady time of 8 hours. When heated, the solid sulfur flakes bring the sulfur partial pressure in the sealed glass tube to 200 Pa-0.2 MPa.

Alternatively, a sulfur partial pressure of 150 Pa to 0.2 MPa can be applied to sulfur-containing gases such as hydrogen sulfide (H ₂ S), carbon disulfide (CS ₂ ) or phosphorus sulfide (P _x S _y , eg P ₄ S _3). , P ₂ S ₃ or P ₂ S ₅ ) can be obtained by sealing in a closed container, such as a sealed glass tube, or by flowing gas through an open container.

Next, the intermediate sintered member is sintered at a sulfur partial pressure of 150 Pa or less and a steady temperature of 200 ° C. to 400 ° C. (step 114) to form a sintered member containing titanium and sulfur.

For example, the intermediate sintered member can be sintered in an open container under an argon atmosphere, that is, by flowing argon through the intermediate sintered member at a steady temperature of 300 ° C. and a steady time of 8 hours. Other gases such as nitrogen, helium, neon and xenon may be used.

Between the two sintering steps 108 and 114, the intermediate sintered member can be polished (step 110) and pressed (step 112). These steps 110 and 112 are optional.

The pressures used in steps 106 and 112 may vary. The pressures used in steps 106 and 112 may be equal. However, the pressure used in both steps 106 and 112 is 25 MPa or higher, preferably 50 MPa or higher, more preferably 75 MPa or higher, 500 MPa or lower, preferably 400 MPa or lower, more preferably 300 MPa or lower.

For example, the pressure in step 106 may be equal to 200 MPa and the pressure in step 112 may be equal to 100 MPa.

The method for producing sample 2 is the same as the method for producing sample 1 except that the member and the intermediate sintered member are sintered under a sulfur partial pressure of less than 150 Pa.

Both the member and the intermediate sintered member are 8 at 400 ° C. under a sulfur partial pressure of less than 150 Pa, for example by sealing the member of sample 2 and the intermediate sintered member in a glass tube with a very low pressure, eg 30 Pa of argon. Sintered in time. Therefore, the sintered member of Sample 2 is sintered at 400 ° C. for 16 hours under a sulfur partial pressure of less than 150 MPa.

2 and 3 show the X-ray diffraction spectra of Sample 1 and Sample 2, respectively. As can be seen from FIGS. 3 and 4, both Sample 1 and Sample 2 have 2θ = 15.08 ° (± 0.50 °) and 15.28 ° (± 0.) in the X-ray diffraction measurement using CuKα rays. 50 °), 15.92 ° (± 0.50 °), 17.5 ° (± 0.50 °), 18.24 ° (± 0.50 °), 20.30 ° (± 0.50 °) ), 23.44 ° (± 0.50 °), 24.48 ° (± 0.50 °), and 26.66 ° (± 0.50 °).

Samples 1 and 2 were sandwiched between two SUS current collectors (stainless steel, SUS301), and the impedances of both sample 1 and sample 2 were measured using an impedance gain phase analyzer manufactured by Biologic. VMP3 manufactured by Biologic was used for measurement as a frequency response analyzer (FRA). The measurement was started from a high frequency range with an AC voltage of 10 mV (millivolt) and a frequency of 1 Hz (Hertz) to 1 MHz.

The electron conductivity of sample 1 is 6.1 × ^10-5 S / cm (Siemens / centimeter). On the other hand, the ionic conductivity of sample 2 is 4.6 × 10 ^-10 S / cm.

Therefore, the electron conductivity of the sintered member was remarkably increased by the sintering under the partial pressure of sulfur of 200 Pa to 0.2 MPa and the subsequent sintering by evaporating the sulfur.

4 and 5 show the real part of the electrical conductivity (S / cm) of each of Sample 1 and Sample 2 which changes according to the frequency (Hz).

Sample 2 shows a clear temperature dependence. On the other hand, Sample 1 shows a very small temperature dependence up to a temperature of 60 ° C. Since the ionic conductivity is strongly temperature-dependent, the quasi-independence of the real part of the electrical conductivity of the sample 1 that changes with frequency indicates that the sintered member of the sample 1 exhibits electron conductivity. Electrical conductivity is the sum of ionic conductivity and electron conductivity.

Sample 1 was obtained by performing all steps 102-114, but similar results can be obtained with or without performing steps 104 and / or steps 110 and 112.

Alternatively, the sulfur partial pressure of 150 Pa or less can be obtained by continuously discharging the gas existing in the closed container including the intermediate sintered member.

Alternatively, the sintered member can be formed by sintering the intermediate sintered member at a gradient temperature where the maximum temperature of the intermediate sintered member is between 200 ° C and 400 ° C (step 114). it can.

For example, the intermediate sintered member is sealed in a glass tube under argon at a very low pressure of, for example, 30 Pa, and is baked at a gradient temperature of 300 ° C. on one side and 100 ° C. on the other side in a sintering time of 8 hours. It may be tied.

When the powder mixture is not amorphized, that is, when step 104 is not performed, in step 106, 25 MPa or more, preferably 50 MPa or more, more preferably 75 MPa or more, 500 MPa or less, preferably 400 MPa or less, more preferably. The powder mixture is pressed at a pressure of 300 MPa or less.

For example, a member is formed by pressing a 100 mg powder mixture at 200 MPa.

In step 108, an intermediate sintered member containing sulfur is formed by sintering the member under a sulfur partial pressure of 200 Pa to 0.2 MPa.

For example, 100 mg of material is charged into a glass tube with 5 mg of sulfur flakes (99.99%) from Sigma-Aldrich® and the glass tube is sealed under very low pressure, eg 30 Pa of argon. An intermediate sintered member containing titanium and sulfur is formed by sintering the member at a steady temperature of over 500 ° C. (Celsius), such as 750 ° C. and a steady time of 10 hours.

Alternatively, the sulfur partial pressure 200Pa~0.2MPa are sealed containers, for example sealed sulfur-containing gas in a glass tube, for example, hydrogen sulfide _(H 2 S), carbon disulfide (CS ₂₎ or phosphorus sulfide ( It can be obtained by sealing P _x S _y , such as P ₄ S ₃ , P ₂ S ₃ or P ₂ S ₅ ), or by flowing gas into an open vessel.

The conditions for sintering 114 of the intermediate sintered member are the same as described above.
Throughout the specification, including the claims, the term "contains" should be understood to be synonymous with "contains at least one" unless otherwise stated. Furthermore, the scope described in the description including the scope of claims should be understood as including the double-ended value unless otherwise specified. It should be understood that the particular values of the described elements fall within the tolerances of manufacturing or industry error known to those of skill in the art. It should be understood that the terms "substantially" and / or "about" and / or "generally" fall within such tolerances.

Although the present disclosure has been described with reference to specific embodiments, it should be understood that these embodiments are merely exemplary of the principles and uses of the present disclosure.

The present specification and examples are illustrative only, and the true scope of the present disclosure is indicated by the following claims.

Claims (15)

A method (100) for producing a sintered member which is a solid electrolyte and / or an electrode containing titanium and sulfur for an all-solid-state battery.
In step (102) of mixing the powders to obtain a powder mixture containing titanium and sulfur,
The step (106) of pressing the member containing the powder mixture and
In order to obtain an intermediate sintered member containing titanium and sulfur, the step (108) of sintering the member under a sulfur partial pressure of 200 Pa to 0.2 MPa, and
In order to obtain a sintered member containing titanium and sulfur, the step (114) of sintering the intermediate sintered member at a partial pressure of sulfur of 150 Pa or less and a steady temperature of 200 ° C. to 400 ° C. is included.
The sintered member has 2θ = 15.08 ° (± 0.50 °), 15.28 ° (± 0.50 °), and 15.92 ° (± 0.92 °) in X-ray diffraction measurement using CuKα rays. 50 °), 17.5 ° (± 0.50 °), 18.24 ° (± 0.50 °), 20.30 ° (± 0.50 °), 23.44 ° (± 0.50 °) ), 24.48 ° (± 0.50 °), and 26.66 ° (± 0.50 °) positions, the method (100). The method (100) according to claim 1, wherein the sulfur partial pressure of 150 Pa or less is obtained by flowing a rare gas or nitrogen through the intermediate sintered member. The method (100) according to claim 1 or 2, wherein the sulfur partial pressure of 150 Pa or less is obtained by continuously discharging the gas existing in the closed container including the intermediate sintered member. A method (100) for producing a sintered member which is a solid electrolyte and / or an electrode containing titanium and sulfur for an all-solid-state battery.
In step (102) of mixing the powders to obtain a powder mixture containing titanium and sulfur,
The step (106) of pressing the member containing the powder mixture and
In order to obtain an intermediate sintered member containing titanium and sulfur, the step (108) of sintering the member under a sulfur partial pressure of 200 Pa to 0.2 MPa, and
Including a step (114) of sintering the intermediate sintered member at a gradient temperature in order to obtain a sintered member, the maximum temperature of the intermediate sintered member is between 200 ° C. and 400 ° C.
The sintered member has 2θ = 15.08 ° (± 0.50 °), 15.28 ° (± 0.50 °), and 15.92 ° (± 0.92 °) in X-ray diffraction measurement using CuKα rays. 50 °), 17.5 ° (± 0.50 °), 18.24 ° (± 0.50 °), 20.30 ° (± 0.50 °), 23.44 ° (± 0.50 °) ), 24.48 ° (± 0.50 °), and 26.66 ° (± 0.50 °) positions, the method (100). The method (100) according to claim 4, wherein the intermediate sintered member is sealed in a closed container during sintering at the gradient temperature. The method according to any one of claims 1 to 5, wherein the sintered member comprises XTi ₂ (PS ₄ ) ₃ , where X is lithium (Li), sodium (Na) or silver (Ag). (100). The method (100) according to any one of claims 1 to 6, wherein the method comprises the step (104) of amorphizing the powder mixture in order to obtain an amorphized powder mixture. The method (100) according to claim 7, wherein the sintering (108) under a sulfur partial pressure of 200 Pa to 0.2 MPa includes a steady sintering temperature of 500 ° C. or lower, preferably 400 ° C. or lower. The method (100) according to claim 7 or 8, wherein the sintering (108) under a sulfur partial pressure of 200 Pa to 0.2 MPa includes a steady sintering time of 20 hours or less, preferably 10 hours or less. The method (100) according to any one of claims 1 to 9, wherein the sulfur partial pressure of 200 Pa to 0.2 MPa is obtained by evaporating solid sulfur. The method (100) of claim 10, wherein the member is placed in a container and sealed under argon at a pressure of 100 Pa or less, preferably 50 Pa or less. The method (100) according to any one of claims 1 to 11, wherein the sulfur partial pressure of 200 Pa to 0.2 MPa is obtained from a sulfur-containing gas. The member is pressed at a pressure of 25 MPa or more, preferably 50 MPa or more, more preferably 75 MPa or more, 500 MPa or less, preferably 400 MPa or less, more preferably 300 MPa or less (106), any one of claims 1 to 12. The method according to item (100). The method according to any one of claims 1 to 13, wherein the intermediate sintered member is polished (110) and pressed (112) between the two sintering steps (108, 114). 100). The polished and pressed intermediate sintered member is pressed at a pressure of 25 MPa or more, preferably 50 MPa or more, more preferably 75 MPa or more, 500 MPa or less, preferably 400 MPa or less, more preferably 300 MPa or less (112). Item 14. The method according to item 14.

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